Investigation of Electrical Hydrogen Detection Properties of Pt/WO3 Thin Films Prepared by Sol-Gel Method

Abstract

Platinum (Pt)nanoparticle-dispersed tungsten trioxide (WO₃₎ thin film is a gasochromic material that changes color from transparent to blue in an H₂ gas atmosphere. The electrical conductivity of Pt-nanoparticle-dispersed WO₃ is dependent on inserted protons and electrons, though the material is insulator in air, because these electrons and protons work as electrical carriers in WO₃. In this study, Pt-nanoparticle-dispersed WO₃ thin films were prepared using the sol-gel process, and the optical and electrical properties were evaluated in an atmosphere with or without H₂ gas. Pt/WO₃ thin films prepared at 400°C showed the largest change in electrical conductivity when exposed to 1% H₂ gas compared with thin films prepared at other temperatures. The electrical conductivity of the film was dependent on an H₂ gas concentration in the range from 100 ppm to 1%. Pt/WO₃ thin films prepared by the sol-gel process are expected to be used for H₂ gas sensor devices due to the linear relationship between the electrical conductivity and H₂ gas concentration.